Menthol is well known for its physiological cooling effect on the skin and mucous membranes of the mouth and has been extensively used as a flavouring agent (methol being a major constituent of oil of peppermint) in foodstuffs, beverages, dentifrices, mouthwashes, etc. and as a component in a wide range of toiletries, liniments and lotions for topical application. Menthol is also a well known tobacco additive for producing a "cool" sensation in the mouth when smoking.
It is well established that the "cooling" effect of menthol is a physiological effect due to the direct action of menthol on the nerve endings of the human body responsible for the detection of hot or cold and is not due to latent heat of evaporation. It is believed that the menthol acts as a direct stimulus on the cold receptors at the nerve endings which in turn stimulate the central nervous system.
Although menthol is well established as a physiological coolant its use, in some compositions, is circumscribed by its strong minty odour and its relative volatility.
Other compounds have been mentioned in the art as having a physiological cooling effect e.g. 2,4,6-trimethyl-4-heptanol (Parfums-Cosmetiques-Savons, May 1956, pages 17-20) and N,N-diethyl-2-ethylbutanamide (French Pat. No. 1,572,332).
The object of the present invention is to provide other compounds having a physiological cooling effect similar to that obtained with menthol but without its attendant disadvantages.
It is a further object of the invention to provide ingestible, topical and other compositions containing such compounds in an amount to provide a physiological cooling effect when such compositions are used in or by the human body.
It is a further object to provide a method of stimulating the cold receptors of the body using agents other than methanol.